Can’t really figure out if it’s a paid App Store or not. I suppose I can have them buy a license externally and have the agent validate that.

Not right now.

    In this early phase, developers can link out from their ChatGPT apps to their own websites or native apps
    to complete transactions for physical goods. We’re exploring additional monetization options over time,
    including digital goods, and will share more as we learn from how developers and users build and engage.

Sounds like vaporware. Any deeper integration beyond in-chat summaries of the actions taken and otherwise linking out would probably be a nightmare.